Locking structure for securing a fluid transfer tube

ABSTRACT

A test sample card is provided with a locking feature for achieving a positive, locking engagement with a transfer tube that conducts fluid into the interior of the test sample card. The locking feature consists of a tubular channel inwardly disposed from the fluid intake port that has an inner annular rim defining a restriction. The annular rim is of a reduced diameter relative to the diameter of the transfer tube. A recessed region is positioned inwardly from the restriction that has an opening in one of the surfaces of the card body. When the transfer tube is inserted into the tubular channel, the first end is forced past the restriction into the recessed region, with the annular rim compressing the transfer tube. The user is able to sense with their hands when the first end is inserted past the restriction. Visual observation of the first end of the transfer tube through the opening in the card surface confirms that the transfer tube has been properly inserted into the test sample card.

BACKGROUND OF THE INVENTION

A. Field of the Invention

This invention relates generally to the field of biological sampletesting apparatus and systems, and more particularly to the subject oftest sample cards which have one or more wells for containing a fluid ortest sample containing a microbiological agent (such as a microorganism)and a reagent, and in which the fluid or test sample is introduced intothe card via a straw-like tube known in the art as a transfer tube.

B. Description of Related Art

A variety of test sample cards are described in the patent literaturewhich have a well or reaction site for receiving a fluid samplecontaining a microbiological agent, such as a microorganism, and areagent. Several representative patents include Meyer et al., U.S. Pat.No. 4,318,994, Charles et al., U.S. Pat. No. 4,116,775; Fadler et al.,U.S. Pat. No. 4,038,151 and Charles et al., U.S. Pat. No. 4,118,280, thecontents of each of which are fully incorporated by reference herein.These patents describe a test sample card having a plurality of wellsarranged in the test sample card body. The reagent is typically loadedin the wells of the card during the completion of manufacture of thecard. The reagent typically comprises a growth medium for amicrobiological agent in a fluid or test sample. It is known to load adifferent reagent in each of the wells of the card in order to performidentification testing of a fluid sample containing an unknownmicrobiological agent or organism. It is also known to use the cards totest the microbiological agent for susceptibility to the antibiotics byloading various antibiotic reagents into the wells.

In the sample testing system described in the Charles et al '280 patent,after the well of the test sample card has been loaded with the fluidsample, the card is incubated for a period of time to promote a reactionbetween the microorganism and the reagent, i.e., growth of themicroorganism. After a period of time, the well is subject to opticalanalysis by a transmittance light source and a detector which arepositioned on opposite sides of the well or by alternate detectionmethods. If the growth medium or reagent is specifically suited for or"matches up" with the particular microorganism in the fluid sample, thepopulation of the microorganism increases substantially, or some otherpredetermined reaction, i.e., chemical reaction, takes place, whichresults in the well turning cloudy and thus having a change in lighttransmission characteristics. The detector determines the amount oflight that is transmitted from the source through the well. By comparingthe transmittance measurement over a period of time, typically severalhours at least, with an initial transmittance measurement, it ispossible to determine whether in fact the reagent and microbiologicalagent are matched by virtue of the change in transmittance measurementreaching a threshold value, such as 25 or 30 percent. The change inlight transmission characteristics therefore can be used to indicate thepresence of a specific microorganism in the well. Identification andsusceptibility may also be detected by absorbency measurements where afluorescent agent is provided in the growth medium.

It is known in the art to introduce the fluid sample into the testsample card using a transfer tube and vacuum techniques. One end of thestraw-like transfer tube is inserted into an intake port in the testsample card. Typically, this is performed manually by a laboratorytechnician at the time the test sample card is used. The free end of thetransfer tube is then inserted into a receptacle, such as a test tube,that contains the fluid sample. The test tube/fluid sample with transfertube and test sample card are then placed as a unit within a vacuumchamber. Vacuum is drawn in the chamber and then released. The releaseof vacuum draws fluid from the receptacle into the fluid passages andwells, loading the wells with fluid.

The present inventors has appreciated that problems have arisen withregards to prior art test sample card and transfer tube arrangements, inthat the user may fail to adequately or properly install the transfertube into the test sample card. When the transfer tube is not properlyinstalled in the card, a potential for air to leak around the transfertube and into the fluid passages in the test sample card exists. The airis then carried by fluid distribution to the test sample wells, wherethe air forms small bubbles in the sample wells. Air bubbles in thewells can adversely affect the accuracy of the reading of the wells bythe optical system. Thus, the inventors have appreciated that the mannerin which the transfer tube is inserted into the test sample card is aimportant performance issue in terms of the ability of the card andassociated optical instrument to perform up to their optimal capability.

The present invention solves the problem of inadequate transfer tubeconnection to the test sample card and resulting leakage of air into thefluid distribution channels by providing a novel locking arrangement inthe test sample card fluid port that insures that the technician hasproperly inserted the transfer tube into the test sample card.

It is therefore a primary object of the invention to provide a testsample card and transfer tube arrangement that achieves a positive,leak-free, locking engagement between the transfer tube and the testsample card fluid port, thereby ensuring optimal performance of the testsample card and optical reading system.

A second object of the invention is to provide a locking feature in atest sample card that is easy to use by the technician, and enables thetechnician to install the transfer tube into the test sample card andimmediately know, by both visual and tactile means, whether the transfertube has been correctly and completely installed in the test samplecard.

SUMMARY OF THE INVENTION

A test sample card is provided having front and rear surfaces and atleast one sample well. The sample well is loaded with a fluid samplefrom a source of the fluid sample via a transfer tube. The test samplecard includes a fluid intake port sized to received a first end of thetransfer tube. An elongate tubular channel is connected to the fluidintake port and has a restriction formed therein. The restrictioncomprises an annular rim of reduced diameter relative to the diameter ofthe first end of the transfer tube.

An inspection station is positioned inwardly in the test sample cardfrom the restriction. The inspection station comprises a recessed regionor chamber sized to receive the first end of the transfer tube after thefirst end has been inserted past the restriction. The chamber is ideallyopen to at least one of the front and rear surfaces of the test samplecard body or otherwise optically clear to thereby allow visualobservation of the first end of the transfer tube in the chamber.

In a preferred embodiment, a stop is provided in the test sample cardpositioned in axial alignment with the fluid intake port and inwardlyfrom the restriction. The stop limits the distance the transfer tube maybe inserted into the test sample card, and prevents the first end of thetransfer tube from interfering with the distribution of the fluid sampleto the sample wells.

When the transfer tube is properly inserted into the tubular channel,the first end of the transfer tube is forced past the restriction intothe recessed region, with the annular rim compressing the transfer tubeto seal off the transfer tube and prevent air bubbles from beingintroduced into the card. The user is able to sense with their handswhen the first end of the transfer tube is inserted past the restrictionto reach the stop. Visual observation of the first end of the transfertube through the opening in the card surface in the inspection stationconfirms that the transfer tube has been properly inserted into the testsample card.

BRIEF DESCRIPTION OF THE DRAWINGS

A presently preferred embodiment of the invention is described below inconjunction with the appended drawing figures, wherein like referencenumerals refer to like elements in the various views, and in which:

FIG. 1 is a plan view of the front surface of a test sample cardincorporating features for locking a transfer tube to the test samplecard;

FIG. 2 is a plan view of the rear surface of the test sample card ofFIG. 1;

FIG. 3 is a side view of the test sample card of FIGS. 1 and 2, showingthe intake port that receives the transfer tube;

FIG. 4 is a plan view of the intake manifold, inspection station, andintake port of the card of FIGS. 1-3, shown greatly enlarged andpartially broken away in order to illustrate the locking features of thepresent invention;

FIG. 5 is a cross-sectional view of the intake manifold, inspectionstation, and intake port of the card of FIG. 4 along the lines 5--5 ofFIG. 4, also shown greatly enlarged;

FIG. 5A is an elevational view of the locking annular rim and channel ofFIG. 4, shown greatly enlarged, taken along the lines 5A--5A of FIG. 4;

FIG. 6 is a plan view of the intake manifold, inspection station, andintake port of the card of FIGS. 1-3, with a transfer tube inserted intothe intake port with the end thereof visible through the inspectionstation, with a portion of the intake port and transfer tube shown indashed lines in order to indicate their position within the card bodybetween the front and rear surfaces of the card body; and

FIG. 7 is an elevational view of the test sample card of FIGS. 1-3 in anassembled condition with a transfer tube, with the free end of thetransfer tube inserted into a test tube containing a fluid sample thatis to be loaded into the test sample card.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, the front surface 10 of a test sample card 12is shown in a plan view. The test sample card 12 incorporates thepresent locking features for locking a straw-like transfer tube 14 tothe test sample card 12. FIG. 2 is a plan view of the opposite rearsurface 16 of the test sample card 12 of FIG. 1. FIG. 3 is a side viewof the test sample card of FIGS. 1 and 2, showing the intake port 18that receives the transfer tube 14.

Before discussing the locking feature of the card 12 per se, otherfeatures of the test sample card that are apparent in FIGS. 1-3 will beaddressed briefly. The test sample card 12 includes a plurality ofsample wells 20 arranged in an array of rows and columns of wells. Thewells 20 are pre-loaded with reagents and/or growth media for fluid ortest samples. The fluid or test sample is loaded into the card 12 bymeans of vacuum loading techniques known in the art. After a transfertube 14 is inserted into the fluid intake port 18 and locked in place inthe manner described below, the fluid is drawn through the transfer tube14 to an intake manifold 22 that supplies fluid distribution channels 24positioned on both the front and rear surfaces of the test sample cardbody. The fluid is carried along the fluid channels 24 to secondarysupply channels 26 that lead to the sample wells 20. Through-card fluiddistribution channels 28 and 28A are provided for supplying fluid fromthe rear supply channels to well supply channels 30 and fluiddistribution channel 24A, respectively, on the front surface 10 of thecard 12.

The sample wells 20 are in communication with bubble trap passages 32that convey any air bubbles that may form in the well to a respectivebubble trap 34 (FIG. 1). Any air bubbles that may be present in thewells as a by product of a test reaction or by fluid distribution tendto migrate to the bubble traps 34, either by virtue of manual jigglingof the card or as a consequence of jostling or tumbling of the cardduring processing or incubation of the card in an analytical instrument.

The wells 20, bubble traps 34, sensor stop holes 36, and many otherfeatures, such as the ramp 38 and raised rail features 40, that are notspecifically related to the present locking feature for the transfertube are described in greater detail in the patent to Raymond E. O'Bearet al., U.S. Pat. No. 5,609,828, assigned to the assignee of the presentinvention, which is fully incorporated by reference herein.Additionally, the front and rear surfaces of the card 12 are preferablycovered with a transparent, high oxygen permeable and transmissibleadhesive membrane as described in the patent application of Patrick Chenet al., application Ser. No. 08/455,404 filed May 31, 1995. The readeris directed to the above '828 and patents for a detailed discussion ofthese features and still other features of the card 12.

The particular locking feature of the present invention consists of afeature that is located in the upper right hand portion of theillustrated card 12 in FIG. 1 in the internal card structure between thefluid intake port 18 and the intake manifold 22, and this feature willbe more particularly described in conjunction with FIGS. 4-7. The portand locking feature on a test sample card may be at other locations onthe test sample card body such as in the cards shown in theabove-referenced Charles et al. patents. The locking feature isapplicable to other fluid connections which utilize a fluid transfertube. FIG. 4 is a plan view of the intake manifold 22, a visualinspection station 54, intake port 18 and an elongate tubular channel 50of the card of FIGS. 1-3, shown greatly enlarged and partially brokenaway in order to illustrate the locking features of the presentinvention. FIG. 5 is a cross-sectional view of the intake manifold 22,inspection station 54, channel 50 and intake port 18 along the lines5--5 of FIG. 4, also shown greatly enlarged. FIG. 5A is an elevationalview of the innermost end of the channel 50 showing the annular rim 52that locks the transfer tube 14, and the channel 64 between two opposedwall portions 62 that allows fluid to be conducted from the transfertube into the intake manifold 22. FIG. 6 is a plan view of the intakemanifold 22, inspection station 54, and intake port 18 of the card ofFIGS. 1-3, with a transfer tube 14 inserted into the intake port 18 withthe first end 56 thereof visible through the inspection station 54. Theterminal end wall of the fluid transfer tube butts against the stop 60of the inspection station 54. In FIG. 6, the elongate tubular channel 50and a portion of the transfer tube 14 are shown in dashed lines in orderto indicate their position within the interior of the card 12 betweenthe front and rear surfaces of the card 12.

Referring to these figures, the locking feature in a preferredembodiment comprises a tubular channel 50 in communication with thefluid intake port 18 that has an annular rim 52 of reduced diameterrelative to the channel 50 and transfer tube 14 that forms a restrictiondisposed at one end thereof opposite the fluid intake port 18. The wallsof the channel 50 are sized to accommodate the first end of the transfertube and guide it towards the frusto-conical taper section 66 and theannular restriction 52. The restriction 52 has a first diameter D1,wherein D1 is slightly less than the outside diameter D of the first endof the transfer tube 14, and less than the diameter of the main body ofthe tubular channel 50. A recessed region forming a chamber 54 isprovided that is disposed in axial alignment with the fluid intake port18 and positioned inwardly in the test sample card from the restriction52. In a preferred embodiment, the recessed chamber 54 is sized toaccommodate the first end 56 of the transfer tube 14 after the first endhas been inserted past the restriction 52, as shown in FIG. 6. Therecessed chamber 54 is preferably formed as an opening in either thefront 10 or the rear 16 surface of the test sample card 12 (or perhapsboth), or is otherwise optically clear, so as to provide an inspectionstation for visually observing whether the first end 56 of the transfertube 14 has been properly and fully inserted into the test sample card.In the embodiment of FIG. 1, the opening for the recessed chamber 54 isformed in the front surface 10 of the test sample card 12. The chamber54 is covered by the transparent adhesive membrane after completion ofmanufacture of the card, as are the wells, the manifold 22, and thefluid channels in the front and rear card surfaces.

A stop 60 is provided comprising a pair of walls 62 separated by avertical gap 64 (see FIGS. 4 and 5A) axially aligned with the fluidintake port 18 and channel 50 inwardly from the restriction 52 relativeto the intake port 18. The vertical gap or channel 64 is sized so as tobe equal to or slightly greater than the diameter of the internal fluidpassageway in the transfer tube 14 so as to not obstruct the flow offluid from the transfer tube into the manifold 22.

The stop 60 limits the distance the transfer tube 14 may be insertedinto the test sample card 12. Further, the stop 60 acts to prevent thetransfer tube 14 from obstructing the intake manifold 22 and interferingwith the proper distribution of the fluid sample to the wells in thecard. In a preferred embodiment, the stop 60 is positioned such that thefirst end of the transfer tube 14 may be inserted a total distance ofbetween 5 and 7 mm into the test sample card, such that the first end 56terminates in the visual inspection station 54, and does not enter theintake manifold 22. The channel 50 could be constructed to be somewhatshorter, with a minimum length of the channel 50, including thefrusto-conical taper section 66, being about 2 mm. Thus, a preferredlength for the channel 50 is between 2 and about 7 mm. A 1 mm deepfrusto-conical tapered entrance 85 with a 20 degree draft angle isprovided which assists the user in inserting the transfer tube into theport 18. Further, in an alternative embodiment, the entire channel 50could be one continuous tapering of the channel walls leading to theannular restriction 52.

When the transfer tube 14 is being inserted into the intake port 18 suchthat the first end 56 abuts the restriction 52, the user perceives anoticeable increase in the resistance or force required to insert thetransfer tube 14 further, owing to the fact that the diameter of thetransfer tube 14 is greater than the diameter of the restriction 52 andan interference or compression of the transfer tube 14 occurs. When theuser pushes slightly harder on the transfer tube 14 to further insertthe transfer tube 14 past the restriction 52, additional force isrequired to deform the first end 56 of the transfer tube 14 slightly andforce it past the restriction. A tapering of the channel 50, such as byproviding a frustoconical region 66 in the inner portion of the channel50 leading to the restriction 52, assists in compressing the transfertube 14, without substantially restricting the internal fluid passagewayof the transfer tube 14. As the first end of the transfer tube 14 ismoved past the restriction 52 and into the recessed chamber 54, asubstantial decrease in insertion force needed to move the transfer tubefurther inward is again noticed in the hands of the user. The first end56 of the transfer tube 14 expands to its original diameter (due to theelastic nature of the plastic transfer tube). The first end 56 isconstrained in the recessed region or chamber 54 by means of the stop 60and the restriction 52, and is visually observed by the opening in thesurface of the card above the chamber 54.

The retention of the first end 56 of the transfer tube 14 by therestriction 52 (as shown in FIG. 6) essentially locks the transfer tube14 to the test sample card 10, such that the transfer tube 14substantially resists pull out forces that may be ordinarily imparted tothe transfer tube. Moreover, by virtue of the elastic deformation of thetransfer tube 14 by the restriction 52 and tight, compressive, positiveengagement of the restriction 52 and the transfer tube 14 body, aneffective seal is created between the exterior surface of the transfertube 14 and the annular restriction 52, preventing air from enteringinto the interior of the card and being distributed to the wells andinterfering with the reading of the wells of the card.

FIG. 7 is an elevational view of the test sample card of FIGS. 1-3 in anassembled condition with a transfer tube 14, with the free end of thetransfer tube 14 inserted into a test tube 70 containing a fluid sample72 that is to be loaded into the test sample card 12. Note the presenceof the first end of the transfer tube in the visual detection station54, indicating that the transfer tube 14 is properly inserted into thetest sample card.

The transfer tube 14 is preferably made from a smooth, deformableplastic material. In the illustrated embodiment, the transfer tube has anominal diameter D of 2 mm, and the restriction diameter D1 is 1.956 mm,but these dimensions could be increased or decreased, along with aproportional increase or decrease in the diameter of the channel 50 forma nominal diameter of 2.138 mm. A preferred composition for the transfertube is a mixture of 74% low density polyethylene, 24% high densitypolyethylene, and 2% color agent. This mixture gives a transfer tubewith the proper harness and resiliency for the illustrated embodiment.Other materials may be suitable for the transfer tube, particularly lowdurometer plastics or blends of such materials, for examplepolypropylene or various grades thereof. The transfer tube need not haveany features at the first end to work with the locking structure in thetest sample card body, and may be smooth.

The distance the transfer tube is inserted into the test sample card isnot particularly important, but as noted above, the locking annular rim52 should be located at least 2 mm inside the opening 18 the card.Referring to FIG. 7, the position of the stop 60 together with thelength of the upper region 76 of the "L" shape in the transfer tubecontrols the position of the downward depending portion 78 and free end80 of the transfer tube 14 relative to the side 13 of the card body. Insome applications, this distance 82 may be important, and theappropriate dimensions should be provided in the portion 76 of thetransfer tube, taking into account the distance the first end of thetransfer tube is inserted into the card.

A preferred analytical instrument for loading the card 12 with the fluidsample via the transfer tube using vacuum, incubating the card, andconducting optical analysis of the wells of the card of FIGS. 1-7 is setforth in the patent application of Mark J. Fanning et al., applicationSer. No. 08/604,672, filed Feb. 21, 1996, which is fully incorporated byreference herein.

We have thus described a testing apparatus comprising a transfer tube 14having a first end and a second end and a test sample card 12 having atleast one well 20 for receiving a fluid sample and a fluid intake port18 formed in an exterior surface of the card. The fluid sample is loadedinto the test sample card by means of the transfer tube 14. The firstend 56 of the transfer tube 14 is for insertion into the fluid intakeport 18 and the second free end is for placement into a receptacle incontact with said fluid sample, for example in the manner shown in FIG.7. The first end 56 of the transfer tube 14 has an outside diameter D.The test sample card further comprises an elongate tubular channel 50 incommunication with the fluid intake port 18 having an inner annular rim52 thereof defining a restriction of a diameter D1, wherein D1<D. Arecessed region 54 is provided that is disposed in axial alignment withthe fluid intake port 18 and positioned inwardly in the test sample card12 from the annular rim 52. The recessed region 54 is sized to receivethe first end of the transfer tube 14 (as shown in FIG. 6) afterinsertion of the first end of the transfer tube past the annular rim 52.The annular rim 52 cooperates with the first end of the transfer tube byproviding a squeezing, interference fit to promote the retention of thetransfer tube and test sample card in an assembled condition when thefirst end of the tube has been inserted into the intake port and intothe recessed region or inspection station 54.

The recessed region 54 preferably comprises an opening in a surface ofthe test sample card body thereby providing an inspection stationpermitting visual observation of the first end of the transfer tube 14.

It will also be appreciated that a method for securing a tubular-shapedtransfer tube 14 into a fluid intake port 18 is set forth herein,comprising the steps of:

a) inserting a first end of the transfer tube 14 into the fluid intakeport 18;

b) pushing the transfer tube 14 further into the fluid intake port 18until the first end 56 of the transfer tube 14 makes contact with arestriction 52 within the fluid intake port 18, the restrictioncomprising an annular rim of reduced diameter relative to the diameterof the first end of the transfer tube;

c) urging the first end of the transfer tube past the restriction 52into a recessed region 54 in axial alignment with the fluid intake port18 and the restriction 52, with the recessed region 54 having a diametergreater than or equal to the diameter of said first end of said transfertube 14 to thereby accommodate the first end of the transfer tube 14after it has expanded to substantially its original diameter; and

d) observing through a window in test sample card (formed in oneembodiment by covering the opening in the recessed region 54 with atransparent adhesive tape) whether the first end of the transfer tube 14has been inserted in the recessed region 54, with the presence of thefirst end of the transfer tube in the recessed region or inspectionstation 54 indicating that the transfer tube 14 has been insertedproperly into the test sample card 12.

In the event that the test sample card further comprises an intakemanifold in axial alignment with the restriction, the method preferablyfurther comprises the step of stopping the insertion of the transfertube 14 at a predetermined location with a stop 60 so that the transfertube 14 does not enter the intake manifold and interfere with thedistribution of the fluid sample through the intake manifold 22 to thewells 20.

As noted above, a presently preferred test sample card for use with theinvention is described in the patent to Raymond E. O'Bear et al., U.S.Pat. No. 5,609,828, which is incorporated by reference. However, theinvention is of course suitable for use with many other types of testsample cards, for example, the test sample cards described in theBackground of the Invention section, supra, and in other similar typesof fluid connection devices. The particular details as to the number,size, shape and arrangement of sample wells, the configuration of thefluid distribution channels, and so on, are not particularly importantto the inventive transfer tube locking feature described herein.

Persons of skill in the art will appreciate that variation may be madeto the preferred embodiment described above without departure from thetrue spirit and scope of the invention. This true spirit and scope isdetermined by the appended claims, to be interpreted in light of theforegoing.

We claim:
 1. In a test sample card comprising at least one well forreceiving a fluid sample and a fluid intake port formed in an exteriorsurface of said card, said fluid sample loaded into said test samplecard by means of a transfer tube having a first end received in saidfluid intake port and a second free end for placement into a receptaclein contact with said fluid sample, said transfer tube having an outsidediameter D, an improvement in said test sample card comprising:a tubularchannel in communication with said fluid intake port having arestriction disposed at one end thereof opposite said fluid intake port,said restriction defining a first diameter D1, wherein D1 is less thanD; a recessed region disposed in axial alignment with said fluid intakeport and positioned inwardly in said test sample card from saidrestriction, said recessed region for receiving said first end of saidtransfer tube after said first end has been inserted past saidrestriction; and a stop positioned in axial alignment with said fluidintake port and recessed region positioned inwardly from saidrestriction, said stop limiting the distance said transfer tube may beinserted into said test sample card; whereby said restriction cooperateswith said first end of the transfer tube to securely and sealinglyengage said transfer tube to said test sample card.
 2. The improvementof claim 1, wherein said transfer tube is made from a deformable plasticmaterial.
 3. The improvement of claim 1, wherein said stop is positionedwithin said test sample card such that said first end of said transfertube may be inserted a total distance of at least 2 mm into said testsample card.
 4. The improvement of claim 1, wherein said recessed regionfurther comprises an opening in said test sample card body or anoptically clear region permitting visual observation of said first endof said transfer tube when said transfer tube has been inserted pastsaid restriction.
 5. The improvement of claim 1, wherein saidrestriction comprises a tapered, frusto-conical surface in said tubularchannel having an innermost rim defining said first diameter D1.
 6. Theimprovement of claim 1, wherein said restriction cooperates with saidtransfer tube to provide a sealing engagement therebetween preventingair from entering into said test sample card between said transfer tubeand said restriction.
 7. Sample testing apparatus, comprising, incombination, a transfer tube having a first end and a second end;a testsample card having at least one well for receiving a fluid sample and afluid intake port formed in an exterior surface of said card, said fluidsample loaded into said test sample card by means of said transfer tube;said first end of said transfer tube for insertion in said fluid intakeport and said second free end for placement into a receptacle in contactwith said fluid sample, said first end of said transfer tube having anoutside diameter D, said test sample card further comprising:(a) anelongate tubular channel in communication with said fluid intake porthaving an inner annular rim thereof defining a first diameter D1,wherein D1<D; (b) a recessed region disposed in axial alignment withsaid fluid intake port and positioned inwardly in said test sample cardfrom said annular rim of said tubular channel, said recessed regionsized to receive said first end of said transfer tube after insertion ofsaid first end of transfer tube past said annular rim, (c) said annularrim cooperating with said first end of said transfer tube to promote theretention of said transfer tube and test sample card in an assembledcondition when said first end of said transfer tube has been insertedinto said intake port and into said recessed region.
 8. The apparatus ofclaim 7, wherein said test sample card further comprises a stoppositioned in axial alignment with said fluid intake port and recessedregion positioned inwardly from said recessed region, said stop limitingthe distance said transfer tube may be inserted into said test samplecard.
 9. The apparatus of claim 7, wherein said transfer tube is madefrom a deformable plastic material.
 10. The apparatus of claim 8,wherein said stop is positioned within said test sample card such thatsaid first end of said transfer tube may be inserted a total distance ofbetween 4 and 8 mm into said test sample card.
 11. The apparatus ofclaim 7, wherein said recessed region further comprises an opening insaid surface of said test sample card body or an optically clear regionthereby providing an inspection station permitting visual observation ofsaid transfer tube when said transfer tube has been inserted into saidtubular channel such that said first end thereof has been inserted pastsaid annular rim.
 12. A test sample card having front and rear surfacesand at least one sample well, said sample well loaded with a fluidsample from a source of said fluid sample via a transfer tube,comprising:a fluid intake port sized to received a first end of saidtransfer tube; a tubular channel connected to said fluid intake port andhaving a restriction formed therein, said restriction comprising aregion of reduced diameter relative to the diameter of said first end ofsaid transfer tube; an inspection station positioned inwardly in saidtest sample card from said restriction, said inspection stationcomprising a chamber sized to receive said first end of said transfertube after said transfer tube has been inserted past said restriction,wherein said chamber is open to at least one of said front and rearsurfaces of said test sample card body or optically clear to therebyallow visual observation of said first end of said transfer tube in saidchamber.
 13. The test sample card of claim 12, further comprising a stoppositioned in axial alignment with said fluid intake port and positionedinwardly from said restriction, said stop limiting the distance saidtransfer tube may be inserted into said test sample card.
 14. The testsample card of claim 12, wherein said transfer tube is made from adeformable plastic material.
 15. The test sample card of claim 13,wherein said stop is positioned within said test sample card such thatsaid first end of said transfer tube may be inserted a total distance ofat least 2 mm into said test sample card.
 16. The test sample card ofclaim 12, wherein said restriction comprises a tapered, surface in saidtubular channel having an innermost rim defining said region of reduceddiameter.